(1) Field of the Invention
This invention relates to the field of knives and other implements having blades (or other features) that are replaceable with the same or different blades (or other features). More particularly, this invention relates to handles that accept and hold a standardized shank portion of a blade or other useful feature. More specifically, the handle may accept and hold a blade such as (for example) a blade commonly known as a “utility” blade or a “box cutter” blade.
(2) Description of Related Art Including Information Disclosed 37 CFR 1.97 and 1.98
The present invention relates to knives and other implements that have blades or other features that are removable. Many implements have blades or other features that are removable because they dull or otherwise wear out. Alternatively, many implements allow substitution of parts that have uses that differ from the substituted part, such as the substitution of a flat-head screwdriver head for a Phillips-head screwdriver head. There is a need for a simpler and better manner of readily releasing an existing blade or other feature, and locking in a new or substitute blade or other feature for use with the remainder of the knife or implement.
Known in the art are various releasable blade-locking knife handles. The following patents are arguably related to the patentability of the subject invention:
U.S. Pat./App. No.1st Inventor NamedDate of Patent/Publication4,777,725HirschOct. 18, 19885,575,071PhillipsNov. 19, 19965,903,983JungmannMay 18, 19996,260,281OkumuraJul. 17, 20016,453,565PhillipsSep. 24, 20026,546,633LovellApr. 15, 20036,612,039KakiuchiSep. 2, 20037,040,023NemaziMay 9, 20067,107,690LuiSep. 19, 20062005/0252010FreemanNov. 17, 2005
U.S. Pat. No. 5,575,071 issued to Phillips discloses a cylindrical blade carrier with a free end having a slot along its central longitudinal axis for receiving the shank of a blade; the shank has a hole aligned with a bore through the sidewall of the blade carrier. Attached around the free end of the blade carrier is a tubular clamp member, for rotation from a 1st position (pushing the ball into seating against the blade hole perimeter to secure the blade to the carrier) to a 2nd position (allowing the ball to un-seat from the blade hole, releasing the blade from the carrier). U.S. Pat. No. 6,453,565 issued to Phillips may be considered comparable to that earlier patent.
Published U.S. patent application Ser. No. 10/847,239 of Freeman discloses a knife having an exchangeable blade, in which the knife handle includes a ball-and-spring mechanism causing the ball to press the blade against the handle wall when the blade is in the cutting position.
U.S. Pat. No. 6,260,281 issued to Okumura discloses a device for mounting a blade on a blade carrier, including a blade pressing member for pressing a blade against a surface of a blade carrier to fix the blade to the carrier; an “operation member” moves the pressing member from that blade-fixed position to a blade-release position by means of a ball interposed between a blade pressing member and the “operation member”. The ball essentially rolls along a surface between those two structural elements, releasing the pressure pushing the blade against the carrier.
U.S. Pat. No. 5,903,983 issued to Jungmann discloses a spindle with a slot for receiving a blade (having a hole in the tang), and blade clamping means for firmly engaging the blade at the blade hole and at two other spots to provide a rigid 3-point support for the blade so affixed within the spindle. One embodiment includes a metallic ball as a blade-engaging member, fixed within a recess so that a portion extends to engage the blade hole.
Those patents do not disclose a ball essentially extending freely through a blade hole while seating in the rim of a hole in an adjacent wall of the blade shank receiver, functioning as either a locking mechanism or a release mechanism depending upon the positioning of the equator of the ball relative to the blade. Neither do those patents disclose use of the blade itself as the part of the lock/release mechanism that either locks the blade more firmly or releases the blade from the receiver. Those patents also do not disclose a magnetized ball having (in a resting position seated in the ball-stop hole within the clevis) its channel equator on the side of the blade nearer to the ball-stop wall. Neither do those patents disclose a means of repositioning the ball so that its channel equator is on the side of the blade nearer to the pass-thru wall.
Rather than pressing against the side surface of a blade to lock it in place by pinning it against a nearby wall, the present invention uses a ball essentially extending freely through the hole of the blade to capture it within a clevis-like receiver; and when the ball is repositioned a small distance, it readily allows the release of the blade as desired.